Correct time formatting in RefreshTableHeaderView

Changed the time for RefreshTableHeaderView. In Australia in the
simulator it would display the time with a trailing "AM" or "PM", but
on the device it would only display "A" or "P". This fixes that and
preserves default date format.
Clear the text of the searchBar if the user taps the search's Cancel button.
This looks like a logic error that causes a crash for empty elements
Fixed some compile warnings
Merge pull request #163 from jstedfast/warning-cleanup

Fixed some compile warnings
Merge branch 'master' of https://github.com/migueldeicaza/MonoTouch.Dialog
Fixing incorrect position of the date picket on an iPad
Adding a BackgroundColor field to the DateTimeElement
Fixed EntryElements to use a separate key for password entries

Fixes http://stackoverflow.com/questions/13706729/why-are-some-of-these-monotouch-dialog-cells-appearing-empty
Merge pull request #165 from jstedfast/password-entry

Fixed EntryElements to use a separate key for password entries
Merge pull request #161 from gratner/master

Potential logic error
NO need to test for the Value, we test that later
Merge remote-tracking branch 'upstream/master'
Merge pull request #159 from ytn3rd/master

Correct displaying of time in update label.
Merge pull request #169 from cosmos21/master

Clear the text of the searchBar if the user taps the search's Cancel button.
Fixed GetImmediateRootElement when called on a Section. Previously it always returned null.

This caused issues with calling GetContainerTableView() on Sections.
Merge pull request #172 from Its-Tyson/section-getroot-issue

Section.GetImmediateRootElement() always returns null
Fixed a bug where DateTimeElements don't show any selection animation due to deriving from StringElement, and StringElements only enabling selection if the Tapped event is subscribed to. DateTime elements overload the OnSelected method and so never have a Tapped subscription. Fixed by forcing to always use a selection style.
Always use the same UITableViewCell, and resize the entry on demand.   Fixes #175
Merge pull request #173 from Its-Tyson/datetime-element-selection-issue

Fixed a bug where DateTimeElements don't show any selection animation.